Drum brake proportional valve

[Gas Pig]

I have several drum brake proportional valves... first question can they go bad? If so is there a way to bench test them to see if they are still good?

Thanks Jeff

 

[hankjr]

FWIW, its pretty easy to take apart, clean and get back together. Mine was seized enough that i had to use a zerk fitting and grease gun to push the valve out. i got new o rings from McMaster Carr i think, cleaned it all up and put it back together. the brake switch itself was also seized. that i had to replace.

Hank

 

[McLeod]

I think the drum brakes only used a distribution block with a switch. It sensed differences between front and back and if so, turn on dash light.
No proportioning going on with it.

 

[Gas Pig]

I think the drum brakes only used a distribution block with a switch. It sensed differences between front and back and if so, turn on dash light.
No proportioning going on with it.

I was under the impression the switch that senses the difference from the front to the back is an internal cylinder that moves to lower pressure side that triggers the switch. Once the switch is tripped there is a procedure to untrip the switch.

I once had a drum brake proportional valve that no mater what I did the switch stayed on. It’s was quite annoying to have the red warning on all the time.

My info could be all wrong too! I’m just trying not to have to do something twice if I could avoid it! lol

Thanks Jeff

 

[McLeod]

Is this what you are referring to?:
https://www.tomsbroncoparts.com/product/drum-brake-junction-block-66-75-early-ford-bronco-used

Wow. Check out that price.

If so, here is how to reset the switch:
https://www.tomsbroncoparts.com/pag...ckprop-valve-brake-warning-switch-adjustment/

 

[Gas Pig]

Is this what you are referring to?:
https://www.tomsbroncoparts.com/product/drum-brake-junction-block-66-75-early-ford-bronco-used

Wow. Check out that price.

If so, here is how to reset the switch:
https://www.tomsbroncoparts.com/pag...ckprop-valve-brake-warning-switch-adjustment/

Yes that’s the one! I’m sure not much to it but I swear I had bad one at one point. Once I’m finished with the truck I don’t want have to go in a swap it out. Maybe I’m just to paranoid! lol

 

[DirtDonk]

Most of them get the shuttle valve stuck on one position or another. Over the years I'd have to say that at least half the Broncos I looked at had the light on the dash constantly lit.
Of those, probably 90% of them were "fixed" by removing the bulb, or unplugging the switch!

Pesky little buggers. So yes, pulling it apart and cleaning the insides could go a long way to getting control of your system back.

Paul

 

[Gas Pig]

Most of them get the shuttle valve stuck on one position or another. Over the years I'd have to say that at least half the Broncos I looked at had the light on the dash constantly lit.
Of those, probably 90% of them were "fixed" by removing the bulb, or unplugging the switch!

Pesky little buggers. So yes, pulling it apart and cleaning the insides could go a long way to getting control of your system back.

Paul

I have a 1/2 dozen of them kicking around so I’ll just do as you suggested and clean them up. I certainly can do that easily enough!

Thanks for both of your guys’ input!!!
jeff